Graph diameter, radius, eccentricity and other properties.
| center(G[, e]) | Return the periphery of the graph G. |
| diameter(G[, e]) | Return the diameter of the graph G. |
| eccentricity(G[, v, sp]) | Return the eccentricity of nodes in G. |
| periphery(G[, e]) | Return the periphery of the graph G. |
| radius(G[, e]) | Return the radius of the graph G. |